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/* bignum_copy.c - copy a bignum
   Copyright (C) 1987, 1990, 1991 Free Software Foundation, Inc.
   
   This file is part of GAS, the GNU Assembler.
   
   GAS is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2, or (at your option)
   any later version.
   
   GAS is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.
   
   You should have received a copy of the GNU General Public License
   along with GAS; see the file COPYING.  If not, write to
   the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.  */

#include "as.h"

#ifdef USG
#define bzero(s,n) memset(s,0,n)
#define bcopy(from,to,n) memcpy(to,from,n)
#endif

/*
 *			bignum_copy ()
 *
 * Copy a bignum from in to out.
 * If the output is shorter than the input, copy lower-order littlenums.
 * Return 0 or the number of significant littlenums dropped.
 * Assumes littlenum arrays are densely packed: no unused chars between
 * the littlenums. Uses bcopy() to move littlenums, and wants to
 * know length (in chars) of the input bignum.
 */

/* void */
int
    bignum_copy (in, in_length, out, out_length)
register LITTLENUM_TYPE *	in;
register int		in_length; /* in sizeof(littlenum)s */
register LITTLENUM_TYPE *	out;
register int		out_length; /* in sizeof(littlenum)s */
{
	register int	significant_littlenums_dropped;
	
	if (out_length < in_length)
	    {
		    register LITTLENUM_TYPE *	p; /* -> most significant (non-zero) input littlenum. */
		    
		    bcopy ((char *)in, (char *)out, out_length << LITTLENUM_SHIFT);
		    for (p = in + in_length - 1;   p >= in;   -- p)
			{
				if (* p) break;
			}
		    significant_littlenums_dropped = p - in - in_length + 1;
		    if (significant_littlenums_dropped < 0)
			{
				significant_littlenums_dropped = 0;
			}
	    }
	else
	    {
		    bcopy ((char *)in, (char *)out, in_length << LITTLENUM_SHIFT);
		    if (out_length > in_length)
			{
				bzero ((char *)(out + out_length), (out_length - in_length) << LITTLENUM_SHIFT);
			}
		    significant_littlenums_dropped = 0;
	    }
	return (significant_littlenums_dropped);
}

/* end of bignum-copy.c */